On directions from which cosmic rays may reach earth satellites

Recent quantitative results are presented to resolve the question of whether sharply curved trajectories of some primary cosmic rays in the magnetosphere may enable particles to gain access to a satellite from a range of directions below the local geometric horizon. It is found that satellites in earth orbit at medium altitudes with orbital inclination of 40 degrees or less may be easily reached by particles from zenith angles well below that of the local geometric horizon. At altitudes of 1250 km and above, particles can reach the satellite from all possible zenith angles.